Search results for " planets and satellites: atmospheres"

A New Look at Spitzer Primary Transit Observations of the Exoplanet HD 189733b

2014

Blind source separation techniques are used to reanalyse two exoplanetary transit lightcurves of the exoplanet HD189733b recorded with the IR camera IRAC on board the Spitzer Space Telescope at 3.6$\mu$m during the "cold" era. These observations, together with observations at other IR wavelengths, are crucial to characterise the atmosphere of the planet HD189733b. Previous analyses of the same datasets reported discrepant results, hence the necessity of the reanalyses. The method we used here is based on the Independent Component Analysis (ICA) statistical technique, which ensures a high degree of objectivity. The use of ICA to detrend single photometric observations in a self-consistent wa…

THE INTERACTION OF THE STELLAR HIGH ENERGY RADIATION WITH THE CIRCUMSTELLAR MEDIUM

The purpose of this Thesis is to study how stellar high energy radiation affects exo- planetary atmospheres. High level of stellar high energy, X-rays and (vacuum end extreme) ultraviolet radiation may prevent planets’ habitability and limit the width of the habitability zone. Such radiation may ionize a star surrounding, affecting the chemistry and thermal bal- ance. The effects of X-rays can be wide ranging or relatively local. Soft X-rays are absorbed closer to the source than X-rays with energy greater than 1 keV. The absorption cross-section of hard X-rays are generally very small, so that such radiation may affect a whole galaxy to some extent. The product of photo-ionization is a cas…